By Jon Eakes
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Construction sites are known to be dusty and dust is not only bothersome, but it can also be deadly, dangerous or even explosive. Asbestos dust proved to be so deadly that the material itself has been banned and any existing clean up requires full HAZMAT protocols.
Small fiberglass fibres are an irritant to the lungs, but although they are about the same size as asbestos fibres, the lungs can actually decompose and clean out small quantities so a simple dust mask is often sufficient for protection. Fine sawdust is literally explosive and allowing a shop atmosphere to be full of such dust is against the fire codes, requiring dust collection at all machines as well as air cleaning devices where needed. Any renovator working in an occupied house knows that dust is his number one customer relations issue.
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Crystalline silica dust from concrete and masonry is a Class I carcinogenic, but it is so common that there is no possibility of banning stone and concrete as was done with asbestos. Although it was identified as a health danger in the Italian quarries over 300 years ago, it wasn’t until 1935 that awareness of the problem became a research and educational concern in the United States. Dust control improved, largely on a voluntary basis and when Occupational Safety and Health Administration (OSHA) was created in 1971 some minimum controls were put into place. It took 35 more years, until the spring of 2016, for the US government through OSHA to establish true worker protection standards for crystalline silica dust in the manufacturing and construction environments. Canada is certain to follow soon.
Over the years, techniques and equipment for controlling dust have developed, largely from the German influence of Bosch, but it is with the legislation regarding silica dust that all manufacturers have been jumping forward the last few years with new and better systems because they knew dust control was going to be severely monitored. Every major tool manufacturer is accelerating their dust control product development, sometimes with accessories that can be used with all tools, often with specific attachments to marry their own tools. HEPA (high-efficiency particulate air) filtered vacuums are the backbone to most dust collection systems, and some work better than others. If the dust goes through poorly sealed joints around the filter, the fancy filter does no good.
Basically, dust control techniques combine one or more of the following:
Ban It
This was done with asbestos and lead in paints.
Make It Heavier
Dust control drywall compound has been around a few years now. When you sand it, the dust particles cling together and become heavy enough to fall to the floor rather than float all over the house.
Wet It
Wet sawing ceramic tiles or concrete solves two problems: It cools the blade and traps the dangerous dust in a water slurry.
Wetting barrels between the tool and the vacuum is actually a form of wet entrapment, especially useful with drywall dust as the water is neither near the water sensitive wall nor near the vacuum. The dust is directed down to the surface of the water where the dust sticks and sinks quickly while the air bounces up and moves on towards the vacuum.
Concrete and masonry demolition sites are one of the primary focuses of the OSHA legislation as this toxic dust floats all over a neighbourhood. Atomized water spray techniques are proving to be very effective on such sites. The company DUST BOSS explains that this is not just a spray of water; when atomized spray control systems produce droplets approximately the same size as airborne particles, they deliver a greater attraction between droplets and dust. Droplet size, water pressure, airflow and velocity are all critical to achieving efficient silica entrapment.
Contain It
Containment can be sealing off a room and working with personal masks while cleaning the air to collect it—or it could be simply a containment device right at the point of dust production directing dust to a vacuum.
Vacuum It
Understand that many shop-vacs can be destroyed by concrete dust, even by the abrasive action of drywall dust. That is why special vacuum techniques are used for fine abrasive dusts, such as:
Although HEPA are the best, a regular vac with a paper bag stops far more of the fine drywall dust than regular filters. Soon we should be seeing equipment certified for working with Silica dust.
A vacuum drawing right near the generation of the dust can certainly help, but efficiencies are multiplied when shrouds actually enclose the dust spray and use the air dynamics of both blade and vacuum flow to trap it all.
There has been quite a development of shrouds added right onto the tool itself, with a long hose off to the vacuum. The concrete or stone surface grinder is one of the worst silica dust makers. If you do not have a vacuum shroud for this tool, run to the store to find one. Some are brand specific, some are universal but most tool manufactures now make them.
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With the cordless revolution, people also want to eliminate that hose, so small battery-operated vacuum and shroud attachments are being made to attach directly to the tools, particularly SDS (slotted drive system) hammer drills. Most of these are specific to one brand; some are universally applicable. Unfortunately, the totally compact solution is getting heavier and heavier with two motors and two batteries plus a dust compartment.
Mid-sized vacuums have been developed into backpacks; giving more vacuum power with the weight on your back and not your arms yet totally cordless and portable.
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In the field of drilling or boring into concrete, particularly on the wall or overhead, there is a surge in the development of shrouds that first use the vacuum power to hold the shroud to the wall or ceiling, while the inflow of air is through brushes that surround the bit. There is no direct contact between the drilling tool and the dust collection system and the shroud can be easily moved from one position to another.
Extract It
The best example of extraction has come with the use of epoxy anchors for bolts and rods. To properly work, the hole needs to be dust free before injecting the epoxy—but getting a dusty hole clean is really difficult and often dusty itself if you use compressed air. Long hollow shaft drills that have a vacuum draw through the bit just above the cutting head and a vac hose connection just before the SDS chuck connection, reduce friction (by taking away the dust), reduce bit heat by the air flow and leave no dust at all behind. Bits last longer and epoxy can be injected immediately.
Whether we like it or not, cleaning up our act is now part of the job and every tool manufacturer is ramping up their dust control options.
Montreal-based TV broadcaster, author, home renovation and tool expert Jon Eakes provides a tool feature in each edition of Home BUILDER. www.JonEakes.com
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